This invention relates generally to X-ray imaging systems and more particularly, to methods of controlling X-ray imaging systems.
In X-ray imaging systems, detector systems may be exposed to a wide range of X-ray radiation fluxes during an exposure that may be due to variations in a patient anatomy and variable X-ray acquisition settings. The wide range of the X-ray flux may require a detector system with a large dynamic range such that the detector system response to relatively high X-ray flux and relatively low X-ray flux are both within predetermined specifications. At least some known X-ray imaging systems use techniques such as surrounding the patient with a water bag or placing “bowtie” filters in the X-ray beam to reduce the required dynamic range of the detector systems. The “bowtie” filters are placed in the X-ray beam to selectively shape the X-ray beam radiation flux to inversely match the patient cross-section. Further, more radiation flux is provided through thicker parts and less radiation flux is provided through thinner parts of the patient anatomy. This results in a more uniform radiation flux profile and reduces the detector dynamic range required.
However, the known detector systems may still require a minimum dynamic range of at least 1,000,000:1 to adequately detect the variations in the X-ray radiation fluxes impinging on the detector systems.